Autonomous tubing casing annulus relief system

Abstract

A system for relieving pressure in a wellbore annulus of a hydrocarbon recovery well includes a wellhead, a production line extending from the wellhead, and an annulus relief line extending between the wellhead and the production line. A first pressure gauge measures fluid pressure in the wellbore annulus, a second pressure gauge measures fluid pressure in the production line. A well control system is in communication with the first pressure gauge, second pressure gauge and a check valve disposed in the annulus relief line. The well control system opens and closes the check valve in response to a determined difference between fluid pressure measured by the first pressure gauge and fluid pressure measured by the second pressure gauge. A related method includes measuring the fluid pressure in the wellbore annulus and in the production line, and opening and closing the check valve in response to the determined pressure difference.

What is claimed is: 
     
       1. A system for relieving pressure in a wellbore annulus of a hydrocarbon recovery well, said system comprising:
 a wellhead disposed at a wellbore; 
 the wellhead including a wing valve; 
 a production line extending from the wellhead; 
 the production line including an insertion valve; 
 an annulus relief line in communication with the wellbore annulus, wherein the annulus relief line extends between the wing valve and the insertion valve; 
 a first pressure gauge that measures fluid pressure in the wellbore annulus; 
 a second pressure gauge that measures fluid pressure in the production line; 
 a one-way check valve that is disposed in the annulus relief line between the wing valve and the insertion valve and that prevents backflow from the production line to the annulus; 
 a counter disposed on the annulus relief line between the check valve and the insertion valve; and 
 a well control system in communication with the first pressure gauge, second pressure gauge and check valve, 
 wherein the well control system opens and closes the check valve in response to a determined difference between fluid pressure measured by the first pressure gauge and fluid pressure measured by the second pressure gauge, and 
 wherein the counter:
 is configured to count instances of fluid flow through the annulus relief line as a result of opening the check valve, 
 is configured to communicate, to the well control system and a supervisory control and data acquisition system (SCADA), a count of a predetermined number of instances of fluid flow through the annulus relief line, and 
 includes a display that provides direct feedback to an operator regarding annulus integrity issues. 
 
 
     
     
       2. The system according to  claim 1 , wherein the well control system opens the check valve when the fluid pressure measured by the first pressure gauge is a predetermined amount greater than the fluid pressure measured by the second pressure gauge. 
     
     
       3. The system according to  claim 2 , wherein the well control system closes the check valve when the fluid pressure measured by the first pressure gauge decreases to a level within a predetermined margin of the fluid pressure measured by the second pressure gauge. 
     
     
       4. The system according to  claim 3 , further comprising:
 an emergency shutdown system in communication with the well control system; 
 wherein the emergency shutdown system is configured to shut-in the well after the predetermined number of instances of fluid flow through the annulus relief line and within a predetermined period of time. 
 
     
     
       5. The system according to  claim 4 , wherein the annulus is a tubing casing annulus disposed between a wellbore casing and production tubing. 
     
     
       6. The system according to  claim 5 , wherein the well control system opens the check valve when the fluid pressure measured by the first pressure gauge is 100 psi greater than the fluid pressure measured by the second pressure gauge. 
     
     
       7. The system according to  claim 6 , wherein the well control system closes the check valve when the fluid pressure measured by the first pressure gauge decreases to a level equal to the fluid pressure measured by the second pressure gauge. 
     
     
       8. A method comprising:
 placing an annulus relief line in communication with a wellbore annulus, such that the annulus relief line extends between a wellhead at a wellbore and a production line extending from the wellhead, 
 wherein the wellhead includes a wing valve and the production line includes an insertion valve, and the annulus relief line extends between the wing valve and the insertion valve; 
 measuring fluid pressure in the wellbore annulus via a first pressure gauge; 
 measuring fluid pressure in the production line via a second pressure gauge; 
 disposing a one-way check valve in the annulus relief line between the wing valve and the insertion valve, wherein the check valve prevents backflow from the production line to the annulus; 
 disposing a counter on the annulus relief line between the check valve and the insertion valve, the counter including a display that provides direct feedback to an operator regarding annulus integrity issues; and 
 via a well control system in communication with the first pressure gauge, second pressure gauge and check valve, opening and closing the check valve in response to a determined difference between fluid pressure measured by the first pressure gauge and fluid pressure measured by the second pressure gauge; and 
 using the counter to:
 count instances of fluid flow through the annulus relief line as a result of opening the check valve, and 
 communicate, to the well control system and a supervisory control and data acquisition system (SCADA), a count of a predetermined number of instances of fluid flow through the annulus relief line. 
 
 
     
     
       9. The method according to  claim 8 , wherein opening and closing the check valve comprises opening the check valve when the fluid pressure measured by the first pressure gauge is a predetermined amount greater than the fluid pressure measured by the second pressure gauge. 
     
     
       10. The method according to  claim 9 , wherein opening and closing the check valve comprises closing the check valve when the fluid pressure measured by the first pressure gauge decreases to a level within a predetermined margin of the fluid pressure measured by the second pressure gauge. 
     
     
       11. The method according to  claim 10 , further comprising:
 providing an emergency shutdown system in communication with the well control system; and 
 configuring the emergency shutdown system to shut-in the well after the predetermined number of instances of fluid flow through the annulus relief line and within a predetermined period of time. 
 
     
     
       12. The method according to  claim 11 , wherein:
 the annulus is a tubing casing annulus disposed between a wellbore casing and production tubing. 
 
     
     
       13. The method according to  claim 12 , wherein:
 the well control system opens the check valve when the fluid pressure measured by the first pressure gauge is 100 psi greater than the fluid pressure measured by the second pressure gauge; and 
 the well control system closes the check valve when the fluid pressure measured by the first pressure gauge decreases to a level equal to the fluid pressure measured by the second pressure gauge.